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MG MGA - Rear Axle Hub Nut Socket

We are having issues with hub nuts on the race cars coming loose.
This is because we cannot get them tight enough. Should be 180 ft lb.
The tin socket offered by Moss and others is not a good fit, and being so long tends to slip off the nut.

So I have arranged for a batch of sockets to be made, to my design, so we can get this nut tightend to the correct torque.

They will be an impact socket, which is a bit over the top, in black and 3/4in drive.

Price is going to have to be £60, no VAT. They will be ready for Stoneleigh in February.

I would appreciate some comments on this, and if there is a really good demand, I can get the price down.

Thanks

Colin
Colin Parkinson

Colin,
You are right about the MOSS product - it is about 1/16th of an inch too big. There is a guy on ebay who sells what looks like a good one made by machining. It is about $40, i.e., about UK pounds 30.
Cheers, Peter.
P. Tilbury

My feeling is that these sockets need a central tube to fit inside the axle housing similar to the original factory tool. This would keep them concentric with the nut centre line.
Mike
Mike Ellsmore

This is what I made. How do your nuts come loose if you use the locking washer?

Art Pearse

The socket made by The British Tool Company in USA is excellent and very solid. Sells direct or on Ebay I think.
Gary Lock

Art, I like your tool, and no doubt you can get it FT. But can you 180 ft lbs?
Problem with racing is we are putting twice as much power through components that are 30 years old, and the sideways thrusts do not do anything for the longevity of the parts. One local team, is now tack welding the nut to the axle!
The tab washer is barely adequate for the job, but the issue is first to get the nut vft!!

I had not seen the Britsih Tool Co part, I will have a look, before we commit to production!

Colin
Colin Parkinson

British Tool Company - anyone got details of web site etc. All links seem to be dead.

Colin
Colin Parkinson

Colin, I could always add length to the arm, but I use a hammer to get it what is tight enough in my opinion, for the time when I will hopefully drive it (normal road use). I've never understood the need for such torque in this application. All it's doing is retaining the inner ball race. In theory there should be no force unscrewing the nut unless the race is spinning. Cornering, I can see like a lever applying torque to the bearing about an axis longitudinal to the car, and if the fit is slack it could force against the nut - but unscrew it?
If you could get it "tight enough" you would not need the lock washer!
Rather than welding the nut, how about solder? At least you could get it off again with heat and not bugger up a good axle.
Or get a custom nut with a few more threads and castellate it and drill the axle for a split pin.
A custom nut would cost less than the tool.
Art Pearse

Hi Art, I hope you are using a bf hammer! Normal road use you probably would not have a problem.
As far unscrewing, it doesnt exactly come unscrewed. more just loose. The tab washer would stop it falling off. The problem with it loosing it's tightness results in the bearing 'flapping' about, and then we get broken drive shafts, even custom made heavy duty ones. You will not believe the cornering forces on modern sticky racing tyres.
It is all down to that damn nut loosening!

As far as a custom nut, the standard nut is only about 1/4 thick, and there is little spare thread on the axle tube to make castelated nuts.

Welding the nut is I think a crazy idea. But it is only a spot of weld, and I do not do it. I think if you soldered it, you have to put alot on or it would break.

Anyway, the whole point of this exercise is to get the nut tight enough before we lock it!

Keep the comments coming!

Thanks

Colin
Colin Parkinson

I've posted this on the MGB BBS...



When I raced a Midget, I invested in a socket for the rear hub nut, but as it was hexagonal, it was readily available...although it was still 3/4" drive. It did get a lot of use though - Midgets only having a single row bearing, rather than the double bearing of the MGB and, presumably, the MGA.

Some Midget racers dispense with the tab washer and used Loctite - me included - and didn't suffer any loose nuts! The theory being that the tab washer is relatively soft and could deform with the extreme cornering forces, allowing the nut to work loose.

I had read of someone fabricating a socket by welding some strips of steel to the end of an old halfshaft (inside) and then welding a large nut to the outside. I had contemplated doing the same but don't have a spare halfshaft. Do you have any broken ones?
Dave O'Neill 2

Colin, found an item by British Tools on Ebay...try Item #140497591947 (it's a Healey item,but you will be able to contact them via it).
Gary
Gary Lock

Gary, cheers mate, and I have found his MG tool as well. It looks little better than the Moss one, just fabricated from tube and too long.
At $45 US I think no contest.
I will proceed with my engineered solution. As soon as I have the sample I will post pics.
It is machined from solid, and altogether a different piece of kit.

Colin
Colin Parkinson

Normally when tightening a bolt it should stretch and will pull the items tight. The longer the bolt, the more stretch and the less it cares about a bit of movement releasing the tension. Here we have a very short "bolt" of sorts and the stretch must be measured in micro-inches I should think. How about a Bellvile washer under the nut?
BTW, how much torque do you think it will take to strip these threads? There are only about 3-4 threads and its not HT steel.
Art Pearse

There aren't many threads but it is a large diameter, so there is a huge surface area.
Dave O'Neill 2

Art, I think you are missing the point of what I am trying to do!
I need to find a way of actually tightening up the nut, in the first instance, to 180ft lb.
Belleville washer - not enough room unless you remove the lock tab.

Dave you have it!

Colin
Colin Parkinson

Colin, I believe you are trying to get enough force on the inner bearing race to stop it moving (laterally and rocking) under lateral forces. That said, if you are getting shafts breaking, it leads me to believe they are bending under the torque induced by the cornering force x the wheel radius. Eg assume 1800 lb car, 40% at rear, all load on one wheel and 2g cornering. force at wheel is 2 x 40% x 1800 = 1440 lb. Wheel radius 13" approx so there is ~ 1500 ft.lb of torque trying to bend the shaft. The stiffness in the bearing and mount are not enough to prevent this bending (*) and probably the tightness plays an insignificant part of preventing it. A shaft that is bending and rotating will eventually fail if the bending is severe enough. I think you need thicker section shafts. So, no matter how tight you get the nut, you will not prevent the shaft from bending under severe cornering forces. My 2c worth!
* Imagine the inner end of the shaft is free and you hauled on the rim with 1500 ft.lb - you would see quite a deflection at the inner end even with a tight bearing.
Art Pearse

Barney discusses the nut in detail: http://mgaguru.com/mgtech/rearaxle/ra102.htm

Steve
Steve Gyles

Hi Colin and everybody.
One more source of the hub nut socket is "Custom Machine Components",USA, www.custommachinecomponents.com
They produce sockets of 1-15/16” size, 45 USD, with smaller tolerance than 1 61/64”.
I ordered their socket just yesterday and hope will receive it in two weeks. If it’s interesting for you
I can check the quality of the socket after receiving and let you know.
Nikolai
Nikolai Skliadnev

Steve, Barney deals with the need to get it tight, and I won't argue with that. Colin's problem is breaking axle shafts and I was trying to analyze why that would be. I can't see the blame is on a slack nut, rather on extreme forces caused by racing conditions. A tight bearing is not going to prevent the bending I described. It would be interesting to hear how and where the shafts are breaking.
Art Pearse

Colin,
Would it be easier/cheaper to have a batch of hexagonal nuts made? I am sure that you would have lots of takers. During my "first" involvement with MGA's during the 70's I am sure that hexagonal replacement nuts were available, in fact I still have the socket - 1 1/8" Whitworth if my memory serves me correctly. Just a thought!


Tony Mitchell

Tony, not thought about that one. But the order for the sockets is placed!

Nikolai thanks for that. I have had a look. Let me know what you think when it arrives.

Steve, thanks for the link to Barney's article. That pretty much sums it up I think.

Colin
Colin Parkinson

Colin,

If you are looking for interested buyers for your batch, I'm interested!

Malcolm
Malcolm Eades

Malcolm, see PM sent direct.

Colin
Colin Parkinson

I have the sockets available now. Picture below.
They are 3/4in drive and actually impact sockets.
I will be at Stoneleigh Sun 20th Feb, and will have some with me.

Phone is 07831 387250.

Price is still going to have to be £60 for this first batch.

Colin



Colin Parkinson

I have just purchased for £33 and used the Metco box spanner. I used a 3/4 inch 3 ft long socket drive and did the nut up as tight as possible easily 180lbs. Absolutely no problem with the box spanner it worked perfectly you just need to keep inwards pressure on it. Colin if your nut is working loose why not use Loctite ?
T Holden

Thanks for that. I bet it isnt 180 ft lb! Cos it will slip off.
Anyway I have made the sockets now. Very difficult to use Loctite as there is always oil around. But you still have to get it tight first.

Remember what I said right at the beginning, this problem is on race cars.

But believe me, these nuts come loose even on road cars.

Colin
Colin Parkinson

Hi Colin - £60 is a bit strong - but good luck in selling them ( I have a large tubular socket that seems to fit ok). Also hoping to be at Stoneleigh - anyone else going?
Cam Cunningham

Colin, I see from your photo that your socket has the eased entrance. This loses you about 1/16" of "bite" on this narrow nut.
Art Pearse

Cam you are correct. It will fit reasonably well, but you will not torque it up to 180 ft lbs without it slipping off!!

Art, well observed, but still enough purchase on the full width of the nut.

Colin
Colin Parkinson

Cam

Yes, planning to be at Stoneleigh. I'll email you my mob.

Steve
Steve Gyles

Friday, I still have a few of the sockets left. Stoneleigh on Sunday Mobile 07831 387250.

Colin
Colin Parkinson

Colin - don't miss the gathering at 12 noon at the MGCC stand - you can hawk your wares then !! - cheers Cam
Cam Cunningham

Thanks to everyone who I met at Stoneleigh.

I now have only 2 of the sockets left.

Anyone interested?

Colin
Colin Parkinson

Hi Colin,
My socket arrived in the U.S. today. It looks very solid and should hold up well.
Thanks, Tony
Tony Shoviak

This thread was discussed between 19/01/2011 and 07/03/2011

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